1. Field of the Invention
The present invention relates to a heat exchanger with a unique orientation of the heat exchanger coils relative to the heat exchanger fan. Specifically the heat exchanger coils of the present invention are oriented so that each heat exchanger coil makes double or compound angles with respect to the plane in which the heat exchanger fan is located. By orienting the coils in this manner relative to the fan, this triangular shaped heat exchanger operates more efficiently than conventional box type heat exchangers.
2. Description of the Related Art
Conventional box type heat exchangers have the heat exchanger coils located in a plane that is perpendicular to a plane in which the fan operates. This orientation is inefficient for several reasons. Air exiting the heat exchanger fan does not flow directly outward at a 90 degree angle from the fan, but instead exits the fan at an angle of approximately 30 degrees. Thus, the air of conventional box type heat exchangers impinges on the heat exchanger coils at approximately a 60 degree angle instead of perpendicularly. This 60 degree angle of impingement has several adverse effects.
First, because the air is impinging on the coil at an angle, the amount of air that passes directly through the coil is reduced, thereby reducing the efficiency of the heat exchanger. The air that does not pass through the coil bounces back into the plenum area of the conventional heat exchanger. This bounced back air causes turbulence and noise. It also causes back pressure on the fan which further decreases the efficiency of the heat exchanger since the fan must now work harder to overcome the increased backpressure within the plenum area of the heat exchanger. Because the fan is working harder against the increased back pressure within the plenum, the operating life of the fan will be shortened.
Additionally, because a reduced amount of air travels through the coil, the discharge air velocity coming from the coil is lower and the hot discharge air can more easily be pulled back into the intake of the fan. This recirculation of hot discharge air through the heat exchanger further decreases the operation efficiency of the conventional box type heat exchanger.
Still another problem with conventional box type heat exchangers is that they do not produce good air flow coverage in the center of the coils or in the corners of the coils. The poor air coverage of these units results in a decrease in the life of their coils and in their associated compressors.
The present invention addresses these problems by providing a triangular shape heat exchanger that has its coils oriented in double or compound angles relative to the plane in which the fan operates. This orientation of the coils allows air from the fan to strike the coils at an angle that is approximately perpendicularly, i.e. the air strikes the coils so that the angle of impact is approximately 90 degrees. This perpendicular angle of impact or impingent has several advantages that increase the efficiency of the present invention.
First, because the air is impinging on the coil perpendicularly, an increased amount of air passes directly through the coil, thereby increasing the efficiency of the present invention. Only a small amount of air will not pass through the coils of the present invention and that air is bounced to the front end of the plenum area where, because of the unique shape of the front end, the air is deflected downward and not back toward the fan. This results in less turbulence, less noise and less static pressure. This translates into a unit that operates more quietly than conventional box type heat exchangers.
Another factor contributing to the quiet operation of the present invention is that less material or metal is employed in building the present invention than is used in conventional box type heat exchangers. By using less metal in its construction, the present invention is less expensive to manufacture. Also, with less metal to vibrate, the present invention operates more quietly.
The present invention produces little back pressure on the fan which further increases the efficiency of the invention since the fan does not have to work harder to overcome an increased backpressure within the plenum area of the heat exchanger. This allows the fan size to be decreased over the size that would normally be required in conventional box type units. This also allows for a higher speed fan to be employed in the present invention. And, less back pressure results in increased fan operating life.
Additionally, because a larger amount of air travels through the coil, the discharge air velocity coming from the coil of the present invention is higher and the hot air is therefore less easily pulled back into the intake of the fan. This eliminates or greatly reduces the recirculation of hot discharge air through the heat exchanger and further increases the operation efficiency of the present invention.
The design of the present invention produces approximately 90% air coverage of the coils whereas conventional box type heat exchangers achieve only about 60% air coverage of the coils. This increase in air coverage results in an increase in the life of the coils and associated compressors. Also, smaller compressors are needed in association with the present invention, resulting in manufacturing cost savings over conventional box type heat exchanger installations.
A further advantage of the present invention is that the present invention has a smaller footprint and therefore takes up less room than conventional box type heat exchangers. This makes the present invention suitable for installations where space is limited.
A still further advantage is that the present invention can be designed to accommodate multiple service heat exchanger coils, thereby allowing a single heat exchanger to serve several different applications. This versatility decreases the number of heat-exchangers required for a facility, resulting in installation and operational savings.